Bimetallic Relays

The bimetallic relays used to deal with overload are generally used with the intention of indirectly protecting from possible overheating different equipment that operate from electricity such as motors and transformers.

The possible overheating of an engine can be caused by factors such as mechanical overload at the shaft end, too high starting time, blocked rotor, lack of a phase, excessive voltage deviations and grid frequency. In case of any of these factors, the current increment, the overcurrent, in the motor will be controlled in all phases by the overload relay.          32664

It is extremely important to remember that all the terminals in the auxiliary circuits of the relay are properly indicated in the same way as the terminals of contactors, which present specific functions. Consequently, the sequence must have nine numbers and if there is a second sequence, it will be identified as number zero. Relays are devices based on the principle of dilatation of thermoelectric parts, also known as bimetallic. The operation of a relay is based on the various expansions that the metals present, if subjected to a temperature variation.